In this day an age this is still making rounds ? So this is the memory usage of cat on my system:

     VSZ   RSS    SZ CMD
    3252  1608   813 /bin/cat

To me there are far more things to worry about than cat. How about your multi-gig browser for one ?

Now for firefox:

        VSZ    RSS     SZ CMD
    3472212 395968 868053 /usr/lib64/firefox/firefox

Maybe people should be looking at that ? I will not even get into modern Linux Desktops :)